WO2018097023A1

WO2018097023A1 - Radiation detection device, radiation image acquisition device, and radiation image acquisition method

Info

Publication number: WO2018097023A1
Application number: PCT/JP2017/041255
Authority: WO
Inventors: 須山　敏康; 達也大西
Original assignee: 浜松ホトニクス株式会社
Priority date: 2016-11-25
Filing date: 2017-11-16
Publication date: 2018-05-31
Also published as: EP3546930A1; EP3546930A4; CN109983325B; EP3546930B1; JP2018084556A; US11079344B2; FI3546930T3; ES2937308T3; US20200057008A1; JP6747948B2; CN109983325A

Abstract

This X-ray detection device 30 is provided with a low-energy scintillator 31 for converting X-rays in a low energy range into scintillation, a low-energy line sensor 32 for detecting the scintillation and outputting image data, a high-energy scintillator 33 for converting X-rays in a high energy range into scintillation, and a high-energy line sensor 34 for detecting the scintillation and outputting image data. The pixels L of the low-energy line sensor 32 and the pixels H of the high-energy line sensor 34 are equal in number and are arranged at the same pixel pitch. Minimum filtering is carried out on the image data from the low-energy line sensor 32, and averaging is carried out on the image data from the high-energy line sensor 34.

Description

Radiation detection apparatus, radiological image acquisition apparatus, and radiological image acquisition method

The present disclosure relates to a dual energy type radiation detection apparatus, a radiation image acquisition apparatus including the radiation detection apparatus, and a radiation image acquisition method, and in particular, the number of pixels of each line sensor and the pixels constituting the radiation detection apparatus. The present invention relates to a dual energy type radiation detection apparatus having the same pitch, a radiation image acquisition apparatus including the radiation detection apparatus, and a radiation image acquisition method.

Patent Documents 1 and 2 disclose a radiation detection apparatus that performs foreign object detection, component distribution measurement, weight measurement, or the like in in-line non-destructive inspection of an object to be inspected conveyed by a belt conveyor or the like. This radiation detection apparatus includes a radiation detector having a scintillator and a line sensor, and generates radiation images by detecting radiation transmitted through an object to be inspected. This radiation detection device is a dual energy type radiation detection device that reduces the pixel area for detecting the low energy range, thereby increasing the contrast difference of the radiation image, and detects the low energy range. A configuration is employed in which the line sensor and the line sensor that detects the high energy range have different numbers of pixels and different pixel pitches. Patent Document 3 discloses a radiation detector suitable for a CT scanner or the like, which is a dual energy type radiation detector having the same number of pixels and the same pixel pitch.

JP 2011-066442 A JP 2011-066443 A JP-A-60-200179

The dual energy type radiation detection apparatus is not limited to this, but real-time processing is desired particularly when acquiring a radiographic image of an object and confirming the presence or absence of a foreign object in in-line nondestructive inspection. For this reason, when each line sensor which comprises a radiation detection apparatus has many pixels, the problem that real-time processing is not in time will arise. On the other hand, if the image data acquired by the pixels of each line sensor is simply thinned out, the contrast difference in the inspection object is reduced, that is, the foreign matter information is removed, and as a result, appropriate radiation is obtained. There is also a possibility that an image cannot be acquired.

Embodiments are intended to provide a radiation detection apparatus, a radiation image acquisition apparatus, and a radiation image acquisition method capable of acquiring an appropriate radiological image and capable of real-time processing as one aspect thereof.

Embodiment of this invention is related with the radiation detection apparatus which detects the radiation which permeate | transmitted the target object conveyed in the conveyance direction as one side surface. The radiation detection apparatus includes: a first scintillator that converts radiation in a low energy range out of radiation transmitted through an object into first scintillation light; and a plurality of second scintillators arranged along a detection direction that intersects a conveyance direction. A first line sensor having one pixel, detecting first scintillation light by the first pixel and outputting first image data, and higher than a low energy range of radiation transmitted through the object A second scintillator that converts radiation in a high energy range into second scintillation light; and a plurality of second pixels arranged along a detection direction that intersects the transport direction. And a second line sensor that detects the scintillation light and outputs second image data. The first pixels of the first line sensor and the second pixels of the second line sensor have the same number of pixels and are arranged at the same pixel pitch. A first thinning process including a minimum filter process is performed on the first image data output from the first line sensor, and a second image data output from the second line sensor is applied to the first image data output from the first line sensor. A second thinning process including an averaging process or an addition process is performed.

In this radiation detection apparatus, a first thinning process including a minimum filter process is performed on the first image data output from the first line sensor that detects radiation in the low energy range, while the high energy range. A second thinning process including an averaging process or an adding process is performed on the second image data output from the second line sensor that detects the radiation of the first line sensor. In this case, a minimum process is performed on the image from the first line sensor for acquiring a radiation image in a low energy range in which the difference between the luminance of the foreign matter and the luminance of the background is relatively large, and the number of pixels is halved. In addition, by leaving low luminance data, it is possible to leave foreign substance information in the image data after the thinning process. On the other hand, an averaging process or an addition process is performed on the image from the second line sensor for acquiring a high-energy range radiation image in which the difference between the brightness of the foreign matter and the brightness of the background is relatively small. And the number of pixels can be halved while preventing foreign matter information from being removed from the thinned image data. As described above, according to this radiation detection apparatus, it is possible to realize real-time processing by reducing the resolution of the acquired radiation image while leaving the information on the foreign matter. Here, the “minimum filter process” is a thinning process in which pixel data having a lower luminance among signals from adjacent pixels is left and the remaining pixel data is removed. The “averaging process” is a thinning process that reduces the amount of data by calculating the average value of the luminance of each signal from adjacent pixels. The “addition process” is the process of calculating the average value of each signal from adjacent pixels. This is a thinning-out process that reduces the amount of data by adding luminance, and is substantially the same process as the averaging process.

The radiation detection apparatus performs a first thinning process including a minimum filter process on the first image data output from the first line sensor and a second output from the second line sensor. An image processing unit that performs a second thinning process including an averaging process or an addition process on the image data may be further provided.

In the radiation detection apparatus, the image processing unit may be capable of switching between a first thinning process including a minimum filter process and a second thinning process including an averaging process or an addition process. In this case, predetermined thinning processing can be sequentially performed on the image data output from the first line sensor and the image data output from the second line sensor, and real-time processing is more reliably performed. be able to.

In the above-described radiation detection apparatus, the second scintillator may be arranged so as to convert the radiation transmitted through the first scintillator into second scintillation light. In this case, since the first and second scintillators are arranged in order with respect to the radiation incident direction (for example, vertically arranged), the target detection can be performed without performing delay control of the radiation detection timing by both scintillators. Imaging of the same position in an object can be performed.

In the above-described radiation detection apparatus, the first and second line sensors may be arranged in parallel with each other across a predetermined region. In this case, since the distance between the first and second line sensors and the radiation source that emits radiation to the inspection object is the same, without performing control in consideration of the expansion rate of the radiation from the radiation source, Imaging of the same position in the object can be performed.

Embodiment of this invention is related with the radiographic image acquisition apparatus provided with the radiation detection apparatus which has one of the structures mentioned above as another aspect. The radiation image acquisition apparatus includes a radiation source that irradiates a target with radiation, a transport unit that moves the target in the transport direction, any of the radiation detection devices described above, and a first that has undergone minimum processing. An image creating apparatus that creates a radiation image based on the converted image data and the second converted image data subjected to the averaging process or the addition process. Also in this case, as described above, it is possible to realize a real-time process by reducing the resolution of an appropriate radiographic image that is acquired while leaving information on foreign matters.

The embodiment of the present invention, as yet another aspect, includes a first scintillator, a second scintillator, a first line sensor having a plurality of first pixels arranged along the detection direction, and a detection direction. And a second line sensor having a plurality of second pixels arranged along the image processing unit, and the first pixel and the second pixel have the same number of pixels and the same pixel pitch. It is related with the acquisition method of the radiographic image which detects the radiation which permeate | transmitted the target object conveyed in the conveyance direction using the radiation detection apparatus arranged in (4). In this radiographic image acquisition method, the first scintillator converts a low-energy range radiation out of the radiation transmitted through the object into the first scintillation light, and the first line sensor first The first detection step of detecting the first scintillation light by one pixel and outputting the first image data, and the second scintillator, the high energy higher than the low energy range among the radiation transmitted through the object A second conversion step for converting the radiation in the range into the second scintillation light, and a second pixel for detecting the second scintillation light by the second pixel of the second line sensor and outputting the second image data. The detection step and the image processing unit perform a first thinning process, which is a minimum filter process, on the first image data, and output a first converted image A first image processing step, and a second image processing step of performing a second thinning process that is an averaging process or an addition process on the second image by the image processing unit and outputting a second converted image And.

In this radiographic image acquisition method, a first image processing step of performing a first thinning process which is a minimum filter process on the first image data and outputting a first converted image, and a second image And a second image processing step of performing a second thinning process, which is an averaging process or an addition process, and outputting a second converted image. In this case, similarly to the above, the minimum processing is performed on the first image from the first line sensor for acquiring the radiation image in the low energy range in which the difference between the luminance of the foreign object and the luminance of the background is relatively large. To reduce the number of pixels to half and leave low-luminance data, so that foreign matter information can be left in the image data after the thinning process. On the other hand, an averaging process or an addition process is performed on the second image from the second line sensor for acquiring a high-energy range radiation image in which the difference between the brightness of the foreign matter and the background brightness is relatively small. It is possible to reduce noise (improvement of S / N) and to reduce the number of pixels while preventing the removal of foreign matter information from the thinned image data. As described above, according to the radiological image acquisition method, it is possible to realize real-time processing by reducing the resolution of the radiographic image acquired while leaving the information of the foreign matter.

In the radiation image acquisition method described above, in the second conversion step, the radiation transmitted through the first scintillator may be converted into second scintillation light by the second scintillator. In this case, since the first and second scintillators are arranged in order with respect to the radiation incident direction (for example, vertically arranged), the target detection can be performed without performing delay control of the radiation detection timing by both scintillators. Imaging of the same position in an object can be performed.

In the above radiographic image acquisition method, the first and second detection steps may be performed by first and second line sensors arranged in parallel across a predetermined region. In this case, since the distance between the first and second line sensors and the radiation source that emits radiation to the inspection object is the same, without performing control in consideration of the expansion rate of the radiation from the radiation source, Imaging of the same position in the object can be performed.

The radiation image acquisition method is based on an irradiation step of irradiating a target with radiation, a transport step of moving the target object along the transport direction, a first converted image, and a second converted image. A generation step of generating a radiographic image. In this case, as described above, it is possible to realize a real-time process by reducing the resolution of an appropriate radiographic image that is acquired while leaving information on foreign matters.

According to the radiation detection device, the radiation image acquisition device, and the radiation image acquisition method according to the embodiment, an appropriate radiation image can be acquired and real-time processing can be performed.

FIG. 1 is a perspective view of an X-ray foreign substance inspection apparatus according to an embodiment. FIG. 2 is a schematic configuration diagram of the X-ray particle inspection apparatus shown in FIG. FIG. 3 is a schematic configuration diagram of an X-ray detection apparatus used in the X-ray foreign substance inspection apparatus shown in FIG. FIG. 4A is an example of a pixel for detecting X-rays in a low energy range in the X-ray detection apparatus shown in FIG. FIG. 4B is an example of a pixel for detecting X-rays in a high energy range in the X-ray detection apparatus shown in FIG. FIG. 5A is a diagram showing an outline of a minimum filter process which is a data thinning process performed by the X-ray detection apparatus shown in FIG. FIG. 5B is a diagram showing an overview of an averaging process which is another thinning process of data performed by the X-ray detection apparatus shown in FIG. FIG. 6 is a schematic configuration diagram showing an outline of a modified example of the X-ray detection apparatus according to the present embodiment.

Hereinafter, embodiments of a radiation detection apparatus, a radiation image acquisition apparatus, and a radiation image acquisition method will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

FIG. 1 is a perspective view of an X-ray foreign substance inspection apparatus according to an embodiment, and FIG. 2 is a schematic configuration diagram of the X-ray foreign substance inspection apparatus shown in FIG. As shown in FIG. 1 and FIG. 2, the X-ray foreign substance inspection apparatus 1 irradiates an inspection object S with X-rays (radiation) from an X-ray source in an irradiation direction Z, and Among these, the X-ray detection apparatus 30 detects X-rays transmitted through the inspection object S in a plurality of energy ranges. The X-ray foreign matter inspection apparatus 1 performs foreign matter inspection, baggage inspection, and the like included in the inspection object S using the transmitted X-ray image. The X-ray foreign matter inspection apparatus 1 includes a belt conveyor 10, an X-ray irradiator 20 that is a radiation source, a dual energy type X-ray detection apparatus 30, and a computer 40.

As shown in FIG. 1, the belt conveyor 10 includes a belt portion 12 on which the inspection object S is placed, and the inspection object S is conveyed in a predetermined manner by moving the belt portion 12 in the conveyance direction Y. Transport in the transport direction Y at a speed. The conveyance speed of the inspection object S is, for example, between 10 m / min and 90 m / min. The inspection object S conveyed by the belt conveyor 10 is, for example, food such as meat, rubber products such as tires, security baggage or cargo, resin products, metal products, minerals such as minerals, separation or resource recovery ( Waste for recycling) or electronic parts.

The X-ray irradiator 20 is an apparatus that irradiates the inspection object S with X-rays directed in the irradiation direction Z as an X-ray source. The X-ray irradiator 20 is a point light source, and is configured so that, for example, its tube voltage can be set between 30 and 80 kV, and its tube current can be set between 0.4 and 3.3 mA. The output can be 12 to 100 w. The X-ray irradiator 20 irradiates by diffusing X-rays within a predetermined angle range in a detection direction X orthogonal (crossing) to the irradiation direction Z and the conveyance direction Y. The X-ray irradiator 20 has a predetermined distance from the belt portion 12 so that the X-ray irradiation direction Z is directed toward the belt portion 12 and diffused X-rays extend over the entire width direction (detection direction X) of the inspection object S. It is arranged above the belt portion 12 at a distance. In the length direction (conveying direction Y) of the inspection object S, the X-ray irradiator 20 sets a predetermined division range in the length direction as an irradiation range, and the inspection object S is conveyed in the conveyance direction Y by the belt conveyor 10. As a result, the entire length direction of the inspection object S is configured to be irradiated with X-rays.

The X-ray detection device 30 detects dual X-ray X-rays transmitted from the X-ray irradiator 20 through the inspection object S in two regions, a low energy range and a high energy range. It is a line detection device. Although a more detailed configuration and function of the X-ray detection device 30 will be described later, the X-ray detection device 30 detects transmitted X-rays in respective high and low energy ranges, and generates image data in each energy range. The X-ray detection apparatus 30 may amplify the generated image data or perform a predetermined correction process. The X-ray detection apparatus 30 outputs these image data to the computer 40.

The computer 40 controls the conveyance and conveyance speed of the belt conveyor 10, the X-ray irradiation by the X-ray irradiator 20, the tube voltage and the tube current, the X-ray detection operation by the X-ray detection device 30, and the like. The computer 40 includes a control unit 41 that mainly performs such control, an image processing unit 42 that processes image data input from the X-ray detection device 30 to generate a subtraction image, and conditions for X-ray detection. And an input device 43 for inputting image processing conditions and the like, and a display device 44 for displaying the acquired X-ray image (radiation image). The computer 40 includes an arithmetic processing circuit for realizing each function and a memory for storing information as a hardware configuration, and is configured by a smart device such as a personal computer or a smartphone and a tablet terminal. The input device 43 is, for example, a touch panel, a mouse, or a keyboard, and the display device 44 is, for example, a display such as a touch panel, a liquid crystal display, or an organic EL display.

Next, the X-ray detection apparatus 30 according to the present embodiment will be described in more detail with reference to FIG. FIG. 3 is a schematic configuration diagram of an X-ray detection apparatus used in the X-ray foreign substance inspection apparatus shown in FIG. As shown in FIG. 3, the X-ray detection device 30 includes a low energy scintillator 31, a low energy line sensor 32, a high energy scintillator 33, a high energy line sensor 34, and a minimum filter processing circuit 35. An averaging processing circuit 36 and a control circuit 37 are provided. The X-ray detection device 30 is a so-called vertical dual energy type radiation line sensor camera in which a low energy line sensor 32 is disposed on a high energy line sensor 34. The control circuit 37 controls operations of the low energy line sensor 32, the high energy line sensor 34, and the like.

The low energy scintillator 31 extends along a detection direction X (a direction orthogonal to the paper surface in the figure) to detect an image of the object S, and X of the low energy range among the X-rays transmitted through the object S. It is a member that converts a line into scintillation light, and is adhered on the light receiving surface of the low energy line sensor 32. As shown in FIG. 4, the low energy line sensor 32 has a plurality of pixels L arranged along the detection direction X on the light receiving surface 32 a and is converted by the low energy scintillator 31 by these pixels L. The scintillation light is detected to acquire low energy image data. The number of pixels L is, for example, 1024 pixels (partially omitted in the figure). In this way, the low energy line sensor 32 detects X-rays in the low energy range.

The high energy scintillator 33 is a member that extends along the detection direction X to detect an image of the object S, and converts X-rays in a high energy range among X-rays transmitted through the object S into scintillation light. Therefore, it is adhered on the light receiving surface of the high energy line sensor 34. As shown in FIG. 4, the high energy line sensor 34 has a plurality of pixels H arranged along the detection direction X on the light receiving surface 34 a and is converted by the high energy scintillator 33 by these pixels H. High energy image data is acquired by detecting the scintillation light. The number of pixels H is, for example, 1024 pixels as in the case of the number of pixels L (partially omitted in the figure). In this way, the high energy line sensor 34 detects X-rays in the high energy range. The high energy range detected by the high energy line sensor 34 is higher than the low energy range detected by the low energy line sensor 32, but the high energy range detected by the high energy line sensor 34 is The low energy range detected by the low energy line sensor 32 is not clearly distinguished, and the energy ranges may overlap to some extent.

Further, in the X-ray detection device 30, the pixels L of the low energy line sensor 32 and the pixels H of the high energy line sensor 34 have the same number of pixels, and the light receiving surfaces 32a and 34a have the same pixel pitch P. Arranged above. As described above, since the pixels L and H have the same number of pixels and are arranged at the same pixel pitch, it becomes easy to match the correspondence relationship of the image data output from the

line sensors

32 and 34, and the subtraction processing or the like. This makes it easier to perform control and makes real-time processing even easier.

The low energy scintillator 31 and the high energy scintillator 33 may be made of the same material, but may be made of different materials. The thicknesses of the low energy scintillator 31 and the high energy scintillator 33 may be the same or different.

When the minimum filter processing circuit 35 receives the image data output from the low energy line sensor 32, the minimum filter processing circuit 35 performs a first decimation process including a minimum filter process on the image data. For example, as shown in FIG. 5 (a), the minimum filter processing circuit 35 has three sets of

image data

100, 110, 90, 80, 70, 100 corresponding to the pixels 1 to 6, in each set. A thinning process is performed to leave the image data with the lower luminance among the signals from the adjacent pixels and remove the other image data. Then, the minimum filter processing circuit 35 performs processing for leaving the luminance 100 as the image data of the pixel 1-2, the luminance 80 as the image data of the pixel 3-4, and the luminance 70 as the image data of the pixel 5-6. As described above, the minimum filter processing circuit performs the thinning process for leaving the pixel data having the lower luminance among the signals from the adjacent pixels and removing the remaining pixel data. The minimum filter processing circuit 35 outputs the converted image data (first converted image data) subjected to the thinning process to the computer 40 as a detection signal.

When the averaging process circuit 36 receives the image data output from the high energy line sensor 34, the averaging process circuit 36 performs a second thinning process including an averaging process on the image data. For example, when there are three sets of

image data

100, 110, 90, 80, 70, 100 corresponding to the pixels 1 to 6, as shown in FIG. A thinning process is performed to reduce the amount of data by calculating an average value of the luminance of each signal from adjacent pixels, and luminance 105 is used as image data for pixel 1-2, luminance 85 is used as image data for pixel 3-4, Processing for setting the luminance to 85 as the image data 5-6 is performed. As described above, the averaging processing circuit 36 performs the thinning process for reducing the data amount by calculating the average value of the luminance of each signal from the adjacent pixels. The averaging processing circuit 36 outputs the converted image data subjected to the thinning process to the computer 40 as a detection signal. The minimum filter processing circuit 35 and the averaging processing circuit 36 constitute an image processing unit that processes an image.

In the image processing unit 42 of the computer 40, difference data between the converted image data for low energy thinned by the minimum filter processing circuit 35 and the converted image data for high energy thinned by the averaging processing circuit 36 is obtained. A calculation process (subtraction process) is performed to generate a subtraction image that is a composite image. Then, the computer 40 outputs and displays the subtraction image generated by the arithmetic processing on a display device 44 such as a display. By this output display, foreign matter or the like contained in the inspection object S can be visually confirmed. Instead of outputting and displaying the subtraction image, only data output may be performed, and foreign matter contained in the inspection object S may be detected directly from the image data by detection processing on the image data. In this way, real-time processing is realized.

Next, an X-ray image acquisition method for detecting X-rays transmitted through the inspection object S transported in the transport direction Y using the X-ray foreign matter inspection apparatus 1 will be described.

In this acquisition method, first, the X-ray irradiator 20 irradiates the inspection object S conveyed by the belt conveyor 10 with X-rays. Then, X-rays in the low energy range among the X-rays irradiated and transmitted to the object S are converted into scintillation light by the low-energy scintillator 31, and the X-rays irradiated and transmitted to the object S are high. X-rays in the energy range are converted into scintillation light by the high energy scintillator 33.

Subsequently, the scintillation light from the low energy scintillator 31 is detected by the plurality of pixels L of the low energy line sensor 32, and the low energy image data is output to the minimum filter processing circuit 35. Further, the scintillation light from the high energy scintillator 33 is detected by the plurality of pixels H of the high energy line sensor 34, and the low energy image data is output to the averaging processing circuit 36. The minimum filter processing circuit 35 performs a first thinning process (see FIG. 5A) that is a minimum filter process on the input low energy image data, and outputs the first converted image to the computer 40. Then, the averaging processing circuit 36 performs a second thinning process (see FIG. 5B), which is an averaging process, on the input high energy image data, and converts the second converted image into the computer 40. Output to. Then, the computer 40 uses these converted images to generate a subtraction image (radiation image) based on the subtraction method.

As described above, in the X-ray foreign substance inspection apparatus 1 including the X-ray detection apparatus 30 according to the present embodiment, a minimum filter is used for image data output from the low energy line sensor 32 that detects X-rays in a low energy range. While the first thinning process including the process is performed, the second thinning process including the averaging process is performed on the image data output from the high energy line sensor 34 that detects the X-rays in the high energy range. It has come to be. For this reason, a minimum filter process is performed on the image from the low energy line sensor 32 for acquiring an X-ray image in a low energy range in which the difference between the luminance of the foreign matter and the luminance of the background is relatively large. By halving the number and leaving low luminance data, it is possible to leave foreign matter information in the image data after the thinning process. On the other hand, the image from the high energy line sensor 34 for acquiring an X-ray image in the high energy range in which the difference between the luminance of the foreign matter and the luminance of the background is relatively small is averaged to reduce noise. The number of pixels can be halved while reducing (improving S / N) and preventing the removal of foreign matter information from the thinned image data. As described above, according to the X-ray foreign substance inspection apparatus 1, it is possible to realize real-time processing by reducing the resolution of an X-ray image acquired while leaving foreign substance information.

Further, in the X-ray detection device 30 according to the present embodiment, the high energy scintillator 33 is disposed so as to convert the X-rays transmitted through the low energy scintillator 31 into low energy scintillation light. For this reason, since each

scintillator

31,33 is arrange | positioned in order with respect to the incident direction of X-ray (for example, arrange | positions vertically), delay control of the X-ray detection timing by both

scintillators

31,33 is performed. In addition, the same position on the object S can be imaged.

The preferred embodiments have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, in the above-described embodiment, an example in which a so-called vertical dual energy type X-ray detection apparatus is used has been described. However, the present invention is not limited to this. For example, as shown in FIG. 6, the low-energy scintillator 31 and the low-energy line sensor 32 and the high-energy scintillator 33 and the high-energy line sensor 34 are arranged in parallel with each other across a predetermined area. The present invention may be applied to a so-called horizontal dual energy type X-ray detection apparatus 30a. The thinning-out processing (minimum filter processing and averaging processing) of the low-energy image data and high-energy image data of the X-ray detection device 30a is the same as described above, but in the X-ray detection device 30a, each of the arranged in parallel Since the distances between the

line sensors

32 and 34 and the X-ray irradiator 20 that emits X-rays to the inspection object S are the same, control is performed in consideration of the magnification rate of the X-rays from the X-ray irradiator 20 and the like. The image of the same position on the object S can be taken without any problem. In the horizontal dual energy type X-ray detection apparatus 30a, the low energy line sensor 32 and the high energy line sensor 34 may be formed on the same substrate. In this case, the column of pixels L of the low energy line sensor and the column of pixels H of the high energy line sensor can be more easily formed in parallel across the dead zone region (predetermined region).

In the above-described embodiment, the example in which the minimum filter processing circuit 35 and the averaging processing circuit 36 for performing the thinning process of the low energy image data and the high energy image data are provided in the X-ray detection apparatus 30 has been described. The minimum filter processing by the processing circuit 35 and the averaging processing by the averaging processing circuit 36 may be performed by the image processing unit 42 of the computer 40. In this case, the low energy detection signal from the line sensor 32 and the high energy detection signal from the line sensor 34 are input to the computer 40, and the computer 40 performs thinning processing such as minimum filter processing and averaging processing. In this case, a part of the image processing unit 42 that performs these image processes may constitute a part of the radiation detection apparatus.

In the above embodiment, the detection signal from the high energy line sensor 34 is averaged by the averaging processing circuit 36 and thinned out. However, instead of this, the detection from the high energy line sensor 34 is performed. An addition process may be performed on the signal. In this case as well, foreign matter information is not removed from the thinned image data, and noise can be reduced (S / N improvement). The “addition process” here is a thinning process that adds the luminance of each signal from adjacent pixels to reduce the data amount, and is substantially the same process as the averaging process described above.

In the above embodiment, the minimum filter processing circuit 35 that performs the thinning process on the detection signal from the low energy line sensor 32 and the averaging process that performs the averaging process on the detection signal from the high energy line sensor 34. Although an example in which the processing circuit 36 is configured in parallel has been shown, one image processing unit to which a detection signal from the low energy line sensor 32 and a detection signal from the high energy line sensor 34 are continuously input In this image processing unit, the image data is counted, and a thinning process (for example, a minimum filter process) is first performed on detection signals for a predetermined number of pixels (for example, the first 1024 pixels). The type of decimation processing is switched, and decimation processing (for example, averaging processing) is performed on detection signals for the next predetermined pixel (for example, the next 1024 pixels). Or addition processing) may be performed. Such a switching process may be performed by the image processing unit 42 of the computer 40.

The embodiment can be applied to, for example, a dual energy type radiation detection apparatus, a radiation image acquisition apparatus including the radiation detection apparatus, and a radiation image acquisition method.

DESCRIPTION OF SYMBOLS 1 ... X-ray foreign material inspection apparatus, 10 ... Belt conveyor, 20 ... X-ray irradiator, 30, 30a ... X-ray detection apparatus, 31 ... Low energy scintillator, 32 ... Low energy line sensor, 33 ... High energy scintillator 34 ... High energy line sensor, 35 ... Minimum filter processing circuit, 36 ... Averaging processing circuit, 40 ... Computer, 42 ... Image processing unit, L, H ... Pixel, P ... Pixel pitch, S ... Inspection object.

Claims

A radiation detection device for detecting radiation transmitted through an object conveyed in a conveyance direction,
A first scintillator that converts low-energy range radiation out of radiation transmitted through the object into first scintillation light;
A first pixel that has a plurality of first pixels arranged along a detection direction that intersects the transport direction, detects the first scintillation light by the first pixel, and outputs first image data. Line sensor,
A second scintillator that converts radiation in a high energy range higher than the low energy range out of radiation transmitted through the object into second scintillation light;
A second pixel having a plurality of second pixels arranged along a detection direction intersecting with the transport direction, detecting the second scintillation light by the second pixel, and outputting second image data; A line sensor,
The first pixels of the first line sensor and the second pixels of the second line sensor have the same number of pixels and are arranged at the same pixel pitch.
The first image data output from the first line sensor is subjected to a first thinning process including a minimum filter process, and the second image data output from the second line sensor. A radiation detection apparatus in which a second thinning process including an averaging process or an adding process is performed.
The first image data output from the first line sensor is subjected to a first decimation process including a minimum filter process, and the second image data output from the second line sensor is applied to the second image data. An image processing unit that performs a second thinning process including an averaging process or an addition process on the image processing unit;
The radiation detection apparatus according to claim 1.
The image processing unit can switch between a first decimation process including the minimum filter process and a second decimation process including the averaging process or the addition process.
The radiation detection apparatus according to claim 2.
The second scintillator is arranged to convert the radiation transmitted through the first scintillator into the second scintillation light.
The radiation detection apparatus according to any one of claims 1 to 3.
The first and second line sensors are arranged in parallel with each other across a predetermined area.
The radiation detection apparatus according to any one of claims 1 to 3.
A radiation source for irradiating the object with radiation;
A transport unit that moves the object in the transport direction;
The radiation detection apparatus according to any one of claims 1 to 5,
An image creation device that creates a radiation image based on the first converted image data subjected to the minimum filter processing and the second converted image data subjected to the averaging processing or the addition processing;
A radiographic image acquisition apparatus comprising:
A first scintillator, a second scintillator, a first line sensor having a plurality of first pixels arranged along the detection direction, and a plurality of second pixels arranged along the detection direction. A radiation detection apparatus having a second line sensor and an image processing unit, wherein the first pixels and the second pixels have the same number of pixels and are arranged at the same pixel pitch. A method for acquiring a radiation image for detecting radiation transmitted through an object conveyed in a conveyance direction,
A first conversion step of converting low-energy range radiation out of radiation transmitted through the object into first scintillation light by the first scintillator;
A first detection step of detecting the first scintillation light by the first pixels of the first line sensor and outputting first image data;
A second conversion step of converting radiation in a high energy range higher than the low energy range out of radiation transmitted through the object into second scintillation light by the second scintillator;
A second detection step of detecting the second scintillation light by the second pixels of the second line sensor and outputting second image data;
A first image processing step of performing a first thinning process, which is a minimum filter process, on the first image data by the image processing unit, and outputting a first converted image;
A second image processing step of performing a second thinning process which is an averaging process or an addition process on the second image data by the image processing unit and outputting a second converted image;
A method for acquiring a radiation image.
In the second conversion step, the radiation transmitted through the first scintillator is converted into the second scintillation light by the second scintillator.
The radiographic image acquisition method according to claim 7.
The first and second detection steps are performed by the first and second line sensors arranged in parallel with each other across a predetermined region.
The radiographic image acquisition method according to claim 7.
An irradiation step of irradiating the object with radiation;
A transport step of moving the object along a transport direction;
A generating step for generating a radiation image based on the first converted image and the second converted image;
The radiographic image acquisition method according to any one of claims 7 to 9, further comprising: